Traveling crane



Feb. 3, 1942.

J. E. MINTY' TRAVELING CRANE Filed Jan. 19, 19 40 3 Sheets-Sheet 1 Feb.3,1942. J. E. MINTY I TRAVELING CRANE I '5 Sheets-Sheet 2 Filed Jan: 19,1940 ME'NEOU 4 v COVEPA Feb. 3, 1 942. M|NTY 2,271,775

' TRAVELING CRANE Filed Jan. 19, 1940 s Sheets-Sheet s I come 0 COVE? 5Patented Feb. 3, 1942 TRAVELING CRANE John E. Minty, Muskegon, Mich.,assignor, by mesne assignments, to Manning, Maxwell & Moore, Inc., acorporation of NewJersey Application January 19, 1940, Serial No.314,610

15 Claims.

The invention relates to improvements in traveling cranes and moreparticularly to cranes for use in raising, lowering and traversing suchmovable members as, for example, the heavy fire brick covers for hightemperature furnaces or soaking pits.

As is well known, soaking pits are ordinarily arranged in side-by-siderelation in one or more rows with their top covers correspondinglyalined. Cranes of the general class here in question are adapted to bepositioned above the covers for raising, lowering and traversing thesame, as billsets or ingots are moved into and out of the p1 One generalobject of the present invention is to provide such a crane which is of acharacter that it may be readily manipulated to raise a selected one ormore of the covers or similar members in a group, all With a maximum offlexibility in the selection of the member to be raised and minimumwastage of time in operation by reason of the selection step.

More specifically, it is an object to provide a traveling crane having aplurality of member engaging means or the like corresponding to eachcover or other member in a row, the crane being of such character thatit may be preliminarily conditioned to raise a selected member ormembers and will thereafter automatically engage, for lifting, only theselected member or members when its member-engaging means or the like isthereafter moved into operative position with respect to the members.

Another object is to provide a crane of the type set forth embodying aplurality of elements movable into and out of positive lockingengagement with respective members to be lifted, as distinguished frommerely gripping the same in the manner of a pair of tongs, together witha single hoisting means for raising and lowering such elements inunison, and a selector type con-, trol for causing them to engage only aselected one or more of the movable members.

Another object is to provide in a crane of the type set forth, andhaving a plurality of member engaging devices or the like arranged to belowered and raised simultaneously by a single hoisting means, animproved actuating means for the member engaging devices such that theycan not only be preliminarily conditioned to subsequently engageautomatically only a selected one or more members when moved intooperative relation therewith, but such that they may also bepreliminarily conditioned to release a selected one or more of themembers which have been previously raised, such disengagement takingplace automatically upon the return of the movable members to loweredposition.

Still another object is to provide a crane of the type indicatedembodying a plurality of individually operated member engaging devicesor the like corresponding to various ones of the movable members to bemanipulated, together with a simple and compact arrangement forsupporting, as well as simultaneously hoisting and lowering, saiddevices and their associated actuating mechanisms.

The invention also resides in the novel form of cover engaging deviceherein disclosed. I

Further objects and advantages of the in-- vention will become apparentas the following description proceeds, taken in connection with theaccompanying drawings in which:

Figure 1 is a plan view of a traveling crane embodying the invention,shown as overlying a row of soaking pit covers.

Fig. 2 is a side elevation, partially in section, of the apparatus shownin Fig. 1.

Fig. 3 is a transverse sectional View taken generally along the line 33in Fig. 1.

Fig. 4 is an enlarged perspective view of one of the sub-frame unitsincluded in the crane of Fi 1. r

Fig. 5 is an exploded perspective view of one of the cover engagingdevices.

Fig. 6 is an end elevation of the device shown in Fig. 5.

Fig. 7 is a wiring diagram of a control circuit used in the crane.

In the exemplary construction the invention has been illustrated asembodied in a traveling crane arranged to manipulate a group of soakingpit covers A, B and C, here shown as three in number and disposed in asingle row (Figs. 1 and 2). It will be understood that any reasonablenumber of covers may be placed in a single row and that further rows,parallel with that shown, may be used if desired. The pit covers A, Band C are of conventional and well known form, each comprising arectangular frame or shell with a heavy refractory lining on its bottomface. These covers close the throats ID of corresponding soaking pitswhich open into a furnace room floor II. The function of the crane is tomanipulate these heavy covers, that is, lift them, traverse themlaterally to expose the pit beneath and then return them to theirinitial positions.

The traveling crane of the present installation comprises a carriage ortrolley, designated generally as I2, arranged to span the row of covers(Figs. 1 and 2). This carriage embodies a pair of longitudinal I-beamside members I3 (see also Fig. 3) rigidly joined by'a series oftransverse beams-I4. To support the carriage I2 for movement in adirection transverse to the row of covers, it is carried on four flangedwheels I5 arranged in pairs at its respective ends and running on railsI6 which extend along the opposite ends of the row of covers andtransverse to the row. The wheels I5 are journaled in end frames I? (seeFig. 3) fixed to the longitudinal I-beams I3.

To traverse the carriage I2 along the rails I5, an electric drivingmotor l8 (Figs. 1 and 2) is utilized. This motor is connected through aspeed reduction gearing IS with a shaft 20, which extends longitudinallyof the carriage I2 and is rotatably journaled in brackets 2| fixed tothe forward I-beam I3. At its opposite ends the shaft 26 is connected indriven relation with the adjacent wheels I5 by drive chains 22 (Fig. 3)located in casings 23. Any suitable form of reversing controller (notshown) may be provided for the traversing motor I8.

In order to effect manipulation of the covers A, B and C, through themedium of a single hoisting mechanism on the crane, intermediateconnecting devices are provided for establishing an operative connectionbetween the hoisting mechanism and any selected cover or covers. To thisend each of the covers is provided with four chan nels or yokes 24(Figs. 2 and 3) fixed to its upper side and engageable by acorresponding set of T- heads 25 on the crane. By oscillating a selectedset or sets of the T-heacls into yoke-engaging position, thecorresponding cover or covers are operatively connected to the hoistingmechanism, such covers and only such covers, being lifted by the singlehoisting mechanism when the latter subsequently raises all of the setsof T-heads in unison.

As the details of the intermediate connecting mechanism, the yokes 24(Figs. 5 and '6) are fashioned as heavy channel shaped castings withinturned lips 26. The side walls and lips of the channels are reenforcedby suitable integral webs 27. Each of these yokes is rigidly bolted tothe metal framework on the top of its corresponding cover. Thecooperating T-heads 25 are of generally rectangular form and areintegral with the depending ends of vertical rods or rock shafts 2B. Ina lateral direction the heads 25 are narrower than the gap between theedges of the yoke lips 25 so that when the head is alined longitudinallywith the yoke (as shown in Fig. 5 and in dot-dash lines in Fig. 6) thehead can move freely in a vertical direction. through the gap in the topof the channel. In a longitudinal direction, however, the heads arelonger than the gaps in the tops of the channels so that when swiveledthrough 90 to the position shown in full lines in Fig. 6, the headswill, upon upward movement of the same, engage the cooperating channelsand lift the attached covers. It will be observed that when the cranecarriage I2 is being traversed along the rails I6 that the heads 25 canmove freely through the channels irrespective of the angular position ofthe heads. The outer ends of the channel are flared, as shown in Fig. 5,so as to prevent any jamming of the heads as they enter the channels.Not only is a strong and positive lock formed by the T-heads andcooperating yokes but is also a very compact one of minimum overallheight. Because no springs or swinging gripper jaws are required thereis little or no liability of breakage of the connecting devices.

To support the T-heads 25 and their actuating mechanisms, separatesub-frames 3!] (Fig. 2) are provided, one such sub-frame being used foreach set of heads. Each of the sub-frames 30 is identical, one beingshown in detail in Fig. 4. It embodies side bars SI, rigidly joined bytwo pairs of intermediate transverse bars 32 and two pairs of endchannels 33. The inner one of each of the end channels 33 is fixed tothe ends of the side bars 3i while the outer channels are fixed to theinner channels with spacer blocks 34 between them. In each of theseblocks 34 is rotatably journaled (by a suitable heavyduty thrustbearing, not shown) the rock shaft 28 of 2. corresponding one of theT-heads 25.

Actuation of the T-heads 25 is, in the present instance, accomplished byelectric solenoids, a pair of engaging solenoids 35 and a pair ofdisengaging solenoids 36 being provided for the set of T-headsassociated with the cover C (Fig. 4). Similar sets of solenoids 35 35and 35 36 actuate the T-heads associated respectively with the covers Aand B (see Fig. '7) Upon reference to Fig. 4 it will be seen that thearmature of each of the T-head engaging solenoids 35 is connected withthe armature of an opposed disengaging solenoid by a rod 31. These rodsare in turn tied together by a cross link 38 rigidly connected to them.The outer ends of this cross link 38 are operatively connected to therespective T-head rock shafts 28 through a suitable linkage includinglongitudinally extending links 39, which are apertured at their centersto receive the inserted ends of the cross link 38 and are pivotallyconnected to the latter. The outer ends of the links 39 are in turnpivotally connected to rocker arms 43, which are rigid with therespective rock shafts 28.

When the engaging solenoids 35 are energized to draw in their armatures,the rods 31 are pulled axially to the left (as viewed in Fig. 4) thusshifting the links 39 endwise in a corresponding direction andoscillating the rock shafts 28 through degrees. The T-heads 25 arethereby twisted angularly the same distance into position to engage thecooperating channels 24. Similarly, upon deenergization of the solenoids35 and energization of the other set 36, the linkage is shifted in theopposite direction and the T-heads 25 returned to the position shown. Itwill be noted that the linkage is not biased in either direction so thatmerely the deenergization of a previously energized set of solenoidswill not shift the linkage.

A single hoisting mechanism is utilized for raising and lowering allthree of the sub-frames 36 in unison, as well as any of the covers whichmay have been engaged by actuation of the corresponding set of T-heads.This hoisting mechanism comprises an electric hoisting motor M (Fig. 1)connected through a worm and worm wheel in a casing 42 and a speedreduction gearing indicated at 43 with a shaft 44, which extendslongitudinally of the carriage I2 and is rotatably journaled in suitablebearing pedestals fixed to the latter. Fixed on this shaft 44 are threepairs of eccentrics 45, one pair for each of the sub-frames 38.Embracing each of these eccentrics is an eccentric strap 45 (see alsoFigs. 3 and 4) and depending from each of the straps is an integral arm41 pivotally connected to an adjacent end of one of the subframes. Thesepivotal connections include transverse pivot pins 48 passing throughregistering holes in the arm 41 and brackets 49, fixed to the sub-frameand channels 33 and embracing the lower ends of the arms. A solenoidbrake 4|a holds the motor 4| against rotation when the motor is idle.

As the hoisting motor 4| rotates the shaft 44 the eccentrics 45 arecorrespondingly rotated (from the position of Fig. 3 to that of Fig. 4during hoisting and vice versa during lowering) to raise and lower thesub-frames 3|] simultaneously. During such a vertical movement thesubframes are guided by the projecting upper ends of the rock shafts 23,which are located at their respective four corners, and are received inguide bushings 28 (Fig. 3) fixed on the transverse beams M of thecarriage l2.

Of particular importance in the present apparatus is the arrangement foreffecting the desired selective actuation of the respective sets ofT-heads 25. In brief, the arrangement is such that the actuatingmechanism may be preliminarily conditioned for moving a selected set orsets of the heads into engaged position while the heads 25 are stilldisplaced from the yokes 24, either in a vertical or horizontaldirection, or both. Then, as soon as the heads are moved into operativerelationwith the yokes 24,1. e. into a position where they are embracedby the latter, the completion of the movement causes the selected headsto be automatically turned into engaged position. Similarly, when aselected one or more of the covers has been elevated by the crane, themechanism may be preliminarily conditioned for their disengagement, theresulting disengagement being instituted automatically and as soon asthe elevated covers have been restored to their initial positions.

By virtue of the provision noted for carrying out what amounts topredetermined cycles of operation in response to preliminary setting ofthe controls much valuable time is saved in the manipulation of thecovers. That such a saving in time is of prime importance will'beapparent when it is borne in mind that the number of such comparativelyexpensive and complicated pieces of apparatus, as the traveling craneshown, which are required for a given number of pit covers, dependsdirectly upon the time consumed in the manipulation of each cover.

The particular control system illustrated (see Fig. '7) is of theelectrical type and includes three master switches S S and 8, associatedwith the cover-engaging devices for the respective covers A, B and C.These switches are of the two-position selector type. Also included inthe controls are sets of switches and 5| associated respectively withthe engaging and disengaging solenoids. In each case the pair ofengaging solenoids 35 and disengaging solenoids 36 for each cover arearranged in parallel connected pairs and one of the switches 50 or 5|,as the case may be, is connected in series with the pair. Each of theseswitches includes a movable switch element mounted on the armature ofone of the associated solenoids and is arranged to be opened when thearmature is fully retracted by energization of the solenoid, and,similarly, to be closed when the armature is pulled in the oppositedirection by the opposed solenoid. Finally, the control arrangementincludes two limit switches, designated generally as 52 and53 (Figs. 1and 2). The limit switch 52 is actuated by rotation of the hoistingshaft 44 and includes a bridging contact 54 (Fig. 7) which is moved tothe closed position shown only when the hoisting shaft is rotated to aposition in which th sub-frames 30 are fully lowered. switch 53 (Fig. 2)is mounted at the end of the carriage and is actuated from its normallyopen position to closed position by a stationary cam 53 mounted alongthe runway in position ,to actuate the switch when the carriage isproperly positioned over the line of pit covers. This switch 53 includesa bridging contact 55 (Fig. 7) which is closed, as shown, only when thecrane is positioned over a row of pit covers. Current for the electricalnetwork is furnished from supply lines L1 and L2.

In the operation of the traveling crane described, it is traversed alongthe rails Hi to a position overlying a selected row of pit covers by thetraversing motor |8. To condition the apparatus preliminarily to lift aselected cover or covers the corresponding ones of the main switches S Sand S are shifted to their engaging positions (to the right as viewed inFig. '7). This preliminary selection operation may be performed eitherwhile the crane is being traversed to a new row or after it has come torest over the selected row. The hoisting motor 4| is set in operation torotate the shaft 44 so that the eccentrics 45 are oscillated from theposition of Fig. 4 to that of Fig. 3. In this way all of the sub-frames30 are lowered simultaneously to a position in which the sets of T-heads25 enter the corresponding channels 24 (position shown in Fig. 2). Thesub-frames can be lowered in this manner either before, after or duringthe traversing, just as is desired, since the T-heads can enter the endsof the yokes 24 or their tops and hence no interference is offered atthis point so long as the T-heads are alined with the path of cranetravel.

As soon as the positioning of the T-heads 25 is completed, asdescribed'above, the limit switch sectors 54 and 55 bridge theircooperating contacts (Fig. '7) thereby completing an energizing circuitfor the selected engaging solenoids. For example, if it is desired toraise the cover A the corresponding master switch S will have beenpreviously shifted to its engaged or right hand position. Consequently,the subsequent closure of the limit switch contacts 54 and 55, at thecompletion respectively of the lowering and traversing movements,energizes the solenoids 35 (through a circuit L154-55--5$50-35 s -L2).Energization of these solenoids 35 causes them to retract theirarmatures thus oscillating the rock shafts 2 8 for the T-heads 25associated with the cover A, through the medium of the linkagepreviously described, into a position in which these T-heads engage thecooperating yokes 24 on the cover A. As soon as the armatures ofsolenoids 35*- reach their fully retracted position thecorrespondingswitch 50 is opened, thereby again deenergizing thesesolenoids so that they will not become overheated during long continuedenergization.

Having engaged the selected cover A in the manner described, thehoisting motor 4| is set in operation to raise all of the sub-frames 30simultaneously. These rising sub-frames will bring with them only theengaged cover A, however, since the other sets of T-heads 25, which haveSimilarly the other limit not been rotated from their disengagedpositions, can move freely away from the associated yokes 24. After thecover A has been elevated the carriage I2 is traversed along the railsl6 so that the cover clears the top of its pit for the insertion orremoval of a billet or ingot. Thereafter, the cover can be restored toits initial position over the pit throat l and other pit covers removedand replaced as desired.

In restoring the cover A to itsinitial position its main switch S isthrown to the disengaged or left hand position (Fig. 7) as a preliminaryoperation while the cover A is still displaced from its pit. It will beobserved that this does not cause the crane to drop the coverimmediately since the limit switch contact 54 is open so long as thehoisting mechanism is not in its lowered position and contact 55 is openso long as the crane is laterally displaced from the row of pits, andhence, a circuit is not completed for the disengaging solenoids 36merely by shifting the switch S After the carriage l2 has been traversedback to a position overlying the row of covers, however, and the cover Alowered to its pit closing position, the limit switch contacts 54 and 55reclose. Thereupon the T-heads are automatically disengaged from thecover A since the solenoids 36 are energized (through a circuitL15455555l36 S L2). En-

ergization of these solenoids 36 oscillates the 3 rock shafts 28, of theT-heads 25 associated with the cover A, back to their initial ordisengaged position. Completion of the retracting movement of thearmatures for the solenoids 3B opens the associated switch 5| therebydeenergizing them and restoring the circuit to the condition shown inFig. '7 preparatory to the performance of subsequent selection cycles.

The function of the switch contacts 54 and 55 in instituting preselectedmovements of the T- heads. or in other words, their function in apositive sense will be clear from the description above. It should alsobe observed that, in a negative sense, they further act as interlocks toprevent oscillation of the T-heads except when the latter are inpredetermined position with respect to the pits and covers.

From the foregoing it will be seen that a traveling crane has beenprovided which is capable of great versatility of operation inmanipulating selected ones of a series of pit covers since the T-heads25 operatively engage the yokes 24 only when the T-heads are rotated toan engaged position, and irrespective of whether or not the T-heads arein raised or lowered position, the crane can be traversed back and forthover the rows of pits with great freedom. Also, particularlycharacteristic of the crane herein disclosed is the speed of operationwhich may be achieved due to the provision of means for preselection ofthe covers which are to be engaged or disengaged and automaticinstitution of the selected operation as soon as the parts are properlypositioned for it to take place. Complete safety of operation is insuredby the arrangement set forth.

The control switches can, of course, be mountedall) on said craneshiftable into and out of engagement with respective ones of saidmembers when positioned in operative relation with them, means on saidcrane for simultaneously raising and lowering all of said devices andany member or members engaged by the latter, actuating means for movingindividual ones of said devices into and out of member-engagingposition, a preselection control means associated with said actuatingmeans for preliminarily conditioning the latter to move a selected oneor more of said devices into member-engaging position, and meansactuated automatically in response to a completion of the movement ofsaid devices into operative relation with the members for institutingthe operation of said actuating means with respect to the preselectedone or ones of said member-engaging devices.

2. The combination of a crane arranged to span longitudinally a row ofmovable members such as soaking pit covers, a plurality of devices onsaid crane shiftable into and out of engage ment with respective ones ofsaid members when positioned in operative relation with them, means onsaid crane for simultaneously raising and lowering all of said devicesand any member or members engaged by the latter, actuating means formoving individual ones of said devices into and out of member-engagingposition, a preselection control means associated with said actuatingmeans for not only conditioning the latter to move a preselected one ofsaid devices into member-engaging position but for also conditioningsaid actuating means to move other selected one or ones of said devicesto memberdisengaging position, and means actuated automatically inresponse to a completion of the movement of said devices into operativerelation with the members for instituting the operation of saidactuating means, to move various ones of said devices to member-engagingand memberdisengaging position in accordance with the preselectionsetting of said control means.

3. The combination of a crane arranged to span longitudinally a row ofmovable members such as soaking pit covers, a plurality of devices onsaid crane shiftable into and out of engagement with respective ones ofsaid members when positioned in operative relation with them, means onsaid crane for simultaneously raising and lowering all of said devicesand any member or members engaged by the latter, actuating means formoving individual ones of said devices into and out of member-engagingposition, preselection control means associated with said actuatingmeans for preliminarily conditioning the latter to move a selected oneor more of said. devices out of member-engaging position, and meansactuated automatically in response to the completion of therepositioning of the members in respective predetermined Positionstherefor for instituting the operation of said actuating means to movethe preselected device or devices to member-disengaging position.

4. The combination of a hoist mechanism movable between raised andlowered positions, intermediate means between the hoisting means and aplurality of movable members such as soaking pit covers for renderingsaid hoisting mechanism operable to raise and lower any selected one ormore of said members, and preselection control means for saidintermediate means operable at will to condition the same preliminarilyto render the hoisting mechanism operative to lift a selected one ormore of said '52,.i7-if775 of memters and including alternativelyenermembers, said control means being automatically operable after suchpreliminary conditioning to effect a completion of the operation of saidintermediate means in response to completion of a predeterminedpositioning of said intermediate means with relation to predeterminedrest positions for said members.

5. The combination of a hoist mechanism movable between raised andlowered positions, intermediate means between the hoisting means and aplurality of movable members such as soaking pit covers for renderingsaid hoisting mechanism operable to raise and lower any selected one ormore of said members, and preselection control means for saidintermediate means-operable at will to condition the same preliminarilyto render the hoisting mechanism operative to lift or to releaseselected ones of said members, said control means being automaticallyoperable after such preliminary conditioning to effect a completion ofthe operation of said intermediate means in response to completion of apredetermined positioning of said intermediate means with relation topredetermined rest positions for said members.

.6. The combination of a crane arranged to span longitudinally a row ofmovable members such as soaking pit covers; a row of abutments carriedby the crane and adapted to engage with mating abutments in respectiveones of the movable members, the pairs of complemental abutments on thecrane and members respectively being movable individually relative toeach other into and out of engagement when positioned in operativerelation; a single hoisting means on the crane for raising and loweringin unison all of the abutments carried by the crane; actuating means foreffecting relative movement between selected pairs of said complementalabutments to shift them into or out of engagement; and interlock meansfor preventing operation of said actuating means except when theabutments carried by the crane are in lowered position.

7. The combination with a group of soaking pit covers alined in a row,of a crane arranged to span the row longitudinally and to move laterallyof it; an abutment on each of said covers and a mating abutment, foreach of those on the covers, carried by the crane, the pairs ofcomplemental abutments being movable individually relative to each otherinto and out of engagement when positioned in operative relation; asingle hoisting means on the crane for raising and lowering in unisonall of the abutments carried by the crane; actuating means for effectingrelative movement between selected pairs of said complemental abutmentsto shift them into or out of engagement; and interlock means forpreventing operation of said actuating means except when the crane islocated in predetermined position over the row of covers.

8. The combination of a hoisting mechanism movable between the raisedand lowered positions, individual means for releasably connecting eachof a plurality of movable articles to be hoisted to the hoistingmechanism, said last named means including pairs of mating mechanicallyengageable members carried respectively by the hoisting mechanism andrespective ones of the movable articles, said members being movablerelative to each other into and out of positive locking engagement whenthe hoisting mechanism is in lowered position, individually operableactuating means for each of said pairs gizable electric circuits, eachof said actuating means being operable to engage and disengage theassociated pair of members upon completionof a corresponding one of saidcircuits, a

manually operable master switching device for each of said actuatingmeans for alternatively closing a pair of contacts in one of saidcircuits for its actuating means and opening a pair of contacts in theother and vice versa, and a limit switch having contacts interposed inall of said circuits and which are closed only when said hoisting meansis in its lowered position.

9; The combination with a plurality of soaking pit covers, of a hoistingmechanism movable between raised and lowered positions, means includingmating abutments carried by the hoisting mechanism andcoversrespectively and engageable in positive locking relation forreleasably connecting individual ones of said covers to the hoistingmechanism, said abutments carried by the hoisting mechanism being raisedand lowered in unison by itjand means for selectively actuatingindividual ones of the mating abutments into and out of engagedposition.

10. A traveling crane comprising, in combination, a wheel-supportedcarriage frame, a plurality of sub-frames movably mounted on saidcarriage frame, a hoisting mechanism on said carriage frame for hoistingand lowering said sub-frames in unison, mechanical connecting devices oneach of said sub-frames movable into and out of load-engaging position,actuators on each of said sub-frames for moving corresponding ones ofsaid connecting devices, and a unified control system for selectivelyoperating said actuating means.

11. A traveling crane comprising, in combination, a wheel-supportedcarriage frame, a plurality of sub-frames movably mounted on saidcarriage frame, a hoisting mechanism on said carriage frame for hoistingand lowering said sub-frames in unison, mechanical connecting devices oneach of said sub-frames movable into and out of load-engaging position,actuators on each of said sub-frames for moving corresponding ones ofsaid connecting devices, a unified control system for selectivelyoperating said actuating means, and interlock means for preventingoperation of said actuators except when all of said sub-frames are intheir lowered positions.

12. A traveling crane for manipulating selected ones of a row of soakingpit covers comprising, in combination, a wheel-supported carriage frame,a plurality of sub-frames movably mounted on said carriage frame ahoisting mechanism on said carriage frame for hoisting and lowering saidsub-frames in unison, a set of load-engaging devices rotatably mountedon each of said sub-frames and each of said devices having an operatingrock shaft operable upon oscillation thereof to move the correspondingdevices into and out of positive locking engagement with complementalabutments on respective ones of the covers, a mechanical linkage on eachsubframe interconnecting the several rock shafts thereon, an actuator oneach of said sub-frames for operating the linkage thereon, and a unifiedcontrol system for selectively operating said actuators.

13. In a traveling crane for manipulating a group of soaking pit covers,the combination of a wheel-supported carriage frame, a plurality ofsub-frames, a vertically extending rock shaft journaled in each of saidsub-frames and. profle ti o g guide mean on i earr s frame end di lsubames for v r cal m emen wi re ne o s id e ri ee r me h i' s means oSai ca a e rame o e s ing and lowering said sub-frames in unison, late lr e n u rd fac n bu men s rigid with the lower ends of said rock shaftsand engageable in positive locking relation with complemental downwardlyfacing rigid abutments on corresponding ones of the pit covers,- andactuators carried by said sub-frames for oscillating said rock shafts.

14. In a traveling crane for manipulating a group of soaking pit covers,the combination of a wheel-supported carriage, a plurality of verticailyextending rock shafts having T-heads on their lower ends engageable withcomplemental abu mem n t o e s n ed term d a e e pee i n ef t -hee emeans o se e ti iy oscillating said rock shafts, and hoisting means onthe carriage for raising and lowering said rock sha t n He sen- 15 In aninstallation of the type set forth the combination of a traveling cranearranged to span longitudinally a row of individually movable members tobe manipulated, a plurality of rock shafts depending from the craneabove respective ones of the movable members and. having T-headsthereon, complemental upwardly facing yokes adapted to be fixed on therespective ones of the movable members, said yokes being shaped topermit the T-heads to pass freely therethrough vertically when theT-heads are alined with the path of crane travel and to engage theT-heads when the latter are turned to a position transverse to the pathof crane travel, and said yokes also being shaped to permit the T-headsto pass freely therethrough in a horizontal direction paralleling thepath of crane movement irrespective of the angular adjustment of theT-heads, means for selectively actuating said rock shafts to turnselected ones of said T- heads into and out of their yoke-engagingpositions, and hoisting means for raising and lowering the rock shaftsin unison.

JOHN E. MINTY.

